[December 14, 2012]MCALLEN, Texas
(AP) -- Three South Texas lawmen, including the son of a prominent county sheriff, were due in court Friday on charges alleging that they and another officer accepted thousands of dollars in bribes to guard shipments of cocaine.

Mission police officer Alexis Rigoberto Espinoza, the fourth alleged conspirator who is himself the 29-year-old son of a police chief, made an initial appearance in federal court in McAllen on Thursday on two counts of cocaine possession with intent to distribute.

His fellow Mission officer, 29-year-old Jonathan Trevino, whose father is Hidalgo County Sheriff Lupe Trevino, was due in court Friday along with two of his father's deputies, Fabian Rodriguez, 28, and Gerardo Duran, 30. All three were taken into custody Thursday, when federal prosecutors announced the charges that have sent shockwaves through the area's law enforcement community.

Prosecutors say the four were members of the "Panama Unit," a task force comprised of officers from their two departments tasked with fighting drug trafficking. Instead of combatting the drug trade, prosecutors say the four provided protection for it.

U.S. Magistrate Judge Dorina Ramos set Espinoza's bail at $100,000 during Thursday's hearing and ordered him to remain under house arrest with electronic monitoring if he should make bail. She denied his request for a court-appointed attorney.

Jonathan Trevino's attorney did not immediately respond to a call for comment and it wasn't known if the other two had lawyers.

Lupe Trevino said he is cooperating fully with the federal investigation and conducting his own internal review, but he added that he also has responsibilities as a father.

"It's been devastating to our family, devastating to the organization," said Lupe Trevino, who as sheriff has accused certain state officials of making Texas' border region sound like a war zone.

"I have to support my son because he is my son. But I will make sure that the right thing is being done and I'm meeting my obligations," Lupe Trevino said. "Nothing is being covered up. I'm being very open with everything."

The sheriff said the FBI came to his office around 3 p.m. Wednesday to tell him two of his deputies were targets of an investigation and that his son was, as well. He said the Panama Unit was formed more than three years ago to help Mission clean up its street-level drug crime, and that he couldn't comment on the specifics of the case because it wasn't his investigation.

Federal prosecutors say the U.S. Immigration and Customs Enforcement department that conducts internal reviews received a tip in August about Espinoza and another task force member stealing drugs. Local police are often assigned to multiagency task forces focusing on drug interdiction. Federal investigators set up a sting.

According to prosecutors, a confidential source working for the government told Duran in September that the drug trafficking organization he was working for needed corrupt law enforcement officers to escort drug loads. On Oct. 19, Duran and another individual escorted a load of 20 kilograms of cocaine north from McAllen to the Border Patrol checkpoint in Falfurrias about an hour away. Duran was allegedly paid $4,000, they said.

The officers earned thousands of dollars more for allegedly escorting four more cocaine shipments in November that were part of the sting operation, prosecutors contend.

The complaint said all four "utilized their positions as law enforcement personnel to escort and protect loads of narcotics." Nothing in the charging documents accuses them of stealing drugs, which was the original tip.

Mission Police Chief Martin Garza said Thursday that Jonathan Trevino was the only officer from his department assigned to the Panama Unit and that Espinoza was assigned to an ICE task force that had its own supervisor. The prosecutor's office didn't immediately respond to an after-hours message Thursday seeking clarification on the matter.

Garza said both officers were fired Thursday. The FBI visited his office late Wednesday afternoon to advise him of their investigation and to collect documents related to it. Garza said he cooperated fully and his department would conduct its own investigation.

If the allegations against his officers are proven, Garza said cases they worked on would have to be reviewed with the district attorney. "There's going to be a domino effect," he said.